For the phenomenon of excessive vibration and noise caused by eccentric load on the tooth surface of the reducer output shaft gear of the construction elevator,taking a construction elevator for construction as the research object,considering the influence of comprehensive factors on the eccentric load of the output shaft helical gear pair,the most overhauled shape was determined through theoretical calculation,and then based on ROAMX,the tooth direction shape was modified by the full factor method,taking the helix modification amount and the tooth top modification amount as the design variables,the parameter optimization design was carried out with the tooth surface contact load distribution coefficient and the tooth root bending load distribution coefficient as the optimization objectives.The optimal modification amount combination result was obtained through calculation.The dynamic simulation analysis of the modified gear shows that the tooth surface contact load and tooth root bending load of the modified gear are more evenly distributed,and the maximum unit length load of the tooth surface is reduced by 58.2%.The dynamic performance of the modified gear was evaluated.The results show that the drive error excitation of the modified gear is reduced by 75.5%,and the acceleration response of the box is reduced by 47.8%.